The present invention is related generally to medical devices. More specifically, the present invention is related to catheters. The present invention includes the bonding of incompatible catheter elements to one another and distal tips for catheters, including balloon angioplasty catheters and stent delivery catheters, and methods of making them.
Arterial blockages, which are also called stenoses, are typically caused by the build-up of atherosclerotic plaque on the inside wall of an artery. In fact, several such stenoses may occur contiguously within a single artery. This can result in a partial, or even complete, blockage of the artery. As a result of the danger associated with such a blockage, several methods and procedures have been developed to treat stenoses. One such method is an angioplasty procedure which uses an inflatable balloon to dilate the blocked artery. A typical inflatable angioplasty device, for example, is disclosed in U.S. Pat. No. 4,896,669.
Catheters are frequently used to carry and deploy stent at target sites within vessels. Stents have come into increasing use to prevent the widened vessel regions from narrowing after angioplasty. A stent, typically having a tubular shape, can be put in place in the widened vessel region to hold the vessel walls apart and the lumen open in the event the vessel attempts to narrow again. One class of stents requires that the stent be forcibly outwardly expanded to put the stent into position against the vessel walls. Another class of stents, self-expanding stents, can be delivered to a site in a compressed or constrained configuration and released in the vessel region to be supported. The self-expanding stent then expands in place to a configuration having a wide lumen, typically pressing firmly against the vessel walls where released. The stent is commonly placed at a recently dilated, stenosed vessel region.
Size and construction of a catheter is usually dictated by the purpose for which they are used. Vasculature targets are usually difficult to reach requiring a device which can navigate tortuous conduits of varying diameter. As such, certain characteristics are commonly desired. In general, a catheter should have a maximum radial extent or profile no larger than necessary, in part to enable the catheter to reach further into narrower vessel regions. Desirable features further include, but are not limited to, flexibility, trackability and adequate column strength, accuracy and ease of use, ease of manufacture and materials which cause minimal damage to the vasculature.
Typically, balloon catheters include, among other elements, a shaft, a balloon mounted thereon and a relatively soft distal tip, used to promote tracking and to reduce damage. Different parts or elements of catheters are typically bonded together via thermal bonding or adhesive bonding. It is to these issues that the present application is generally directed, taking into consideration general desired features of catheter design and construction.
All US patents and applications and all other published documents mentioned anywhere in this application are incorporated herein by reference in their entirety.
Without limiting the scope of the invention a brief summary of some of the claimed embodiments of the invention is set forth below. Additional details of the summarized embodiments of the invention and/or additional embodiments of the invention may be found in the Detailed Description of the Invention below.
A brief abstract of the technical disclosure in the specification is provided as well only for the purposes of complying with 37 C.F.R. 1.72. The abstract is not intended to be used for interpreting the scope of the claims.